in keeping with tradition, president obama laid a wreath at the tomb of the unknowns at arlington national cemetery. he said as u.s. combat troops wind down their mission in afghanistan, the country must not forget their sacrifices. >> our troops wear the uniform for a time, yet they wear another proud title, the title of "veteran," for decades, for the rest of their lives. as a nation, we make sure we have the best-led, best-trained, best-equipped military in the world. we have to devote just as much energy and passion to making sure we have the best cared-for, best-treated, best-respected veterans in the world. >> ifill: one of the nation's oldest veterans attended the arlington ceremonies. richard overton is 107 years old, and lives in texas. he was in the army in world war two, and served at pearl harbor, okinawa and iwo jima. two weeks of climate change negotiations have opened in warsaw, poland. envoys from 190 countries will discuss how to cut emissions of carbon dioxide and other greenhouse gases linked to rising global temperatures. united nations officials hope to lay the groundw